Update nto1 selective model

Update nto1 selective model

The nto1 selective wakeup model introduced by Paolo was:

a) too complex (tried to model the full-blown RCU rather than a simple
   queue system)
b) did not model progress with wakers running for a limited amount of
   iterations, only with wakers running infinitely often (which
   therefore does not prove anything).

What we really want to model here is what happens if we have wakers
running a few times, and then not running for a very long time: can we
end up with a missed wakeup, and therefore end up with an enqueued entry
but with the waiter waiting forever ?

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>